This paper argues that psychoanalysis enables us to see mental disorder as rooted in emotional conflicts, particularly concerning aggression, to which our species has a natural liability. These can be traced in development, and seem rooted in both parent-offspring conflict and in-group cooperation for out-group conflict. In light of this we may hope that work in psychoanalysis and neuroscience will converge in indicating the most likely paths to a better neurobiological understanding of mental disorder.